Such a move would help curb the rapid increase of overdoses and addiction that has been fueled by the powerful narcotics, said Andrew Kolodny, president of Physicians for Responsible Opioid Prescribing.

Others countered at a two-day meeting such a change would mean people who desperately need the drugs would not have access to them.

The Journal Sentinel reported this week that the drugs increasingly have been prescribed for chronic pain, an area where their safety and effectiveness are unproven, especially for older patients.

Since 2007, top-selling opioids dispensed to people 60 years and older have increased 32%, double the rate for those in the 40-to-59 age group.

Past investigations have focused on the pharmaceutical industry's financial influence with groups that advocate for greater opioid usage. In February, the Journal Sentinel reported that a network of pain organizations , doctors and researchers pushed for expanded use of opioids while taking in millions of dollars from companies that make the drugs.

The stories were among those that last month prompted a U.S. Senate investigation into financial ties between drug makers, doctors and the groups.

The testimony to the U.S. Food and Drug Administration was part of a two-day meeting to discuss what is known about the effectiveness of opioids in treating chronic pain. The meeting ended Thursday.

"We need to start with science," said Douglas Throckmorton, the FDA's deputy director of the Center for Drug Evaluation and Research. "We know less than we would like to about chronic, non-cancer pain."

Opioids are approved to treat moderate to severe pain. But those approvals, also known as labeling of a drug, do not specify whether they are safe to use for long periods of time.

Long-term studies on chronic pain and opioids have not been done, said Michael Von Korff, senior investigator for the Group Health Research Institute in Seattle. Clinical trials usually last only 12 weeks, he said, plus opioids were approved decades ago when standards for approval were lower.

Determining what a drug is approved for is important because it affects how the products are marketed.

Pharmaceutical companies are only allowed to market drugs for uses that have been approved by the FDA. But doctors can and often do prescribe drugs "off-label," or for conditions or uses for which the drug was not approved.

Advocates believe that making it clear opioids have not been proven safe and effective for treating chronic pain would limit prescribing of the drugs.

"I'm here to get the truth out," said Harris Silver, a doctor from New Mexico who said he was addicted to opioids after a car crash and surgeries over the past decade.

Not everyone supports the proposed change.

Heather Pierce, a 37-year-old with a genetic connective tissue disorder called Ehlers-Danlos syndrome, said she is worried that limiting the approval of opioids to just severe pain would make it harder to get for people who need it to live. Health insurance companies also might balk at paying for the drug if it needed to be prescribed off-label.

"It is limiting access to people who need it," said Pierce, who has taken prescription opioids for five years.

More evidence

The FDA's Throckmorton said more evidence needs to be examined before a labeling change would be considered - and added that approach is just one way to approach the opioid problem.

"FDA can't solve this alone," he said. "Academics can't solve this alone. Patient groups can't solve this alone. We need to be doing a great many things and not a single thing."

Opioid makers rejected the idea of a label change.

"The current approved label for OxyContin is appropriate as it accurately reflects the patient population studied in multiple clinical investigations," Shirley Johnson, a spokeswoman for Purdue Pharma, said in an email to the Journal Sentinel. "The studies evaluated patients suffering chronic moderate-to-severe cancer and non-cancer pain."

In a statement, Purdue Pharma said the under-treatment of pain is a public health burden.

"When used as directed, opioid pain medicines are an important treatment option for health care professionals, and provide therapeutic benefit to millions of people living with chronic pain," the company said. "While opioids are often used in combination with other therapies, for many people with moderate-to-severe chronic pain, there is no single adequate medicinal substitute for opioids."

Jeff Christensen, a spokesman for Janssen Pharmaceuticals, said the company's opioid products are FDA-approved for use in treating moderate-to-severe chronic pain. The uses are based on data from clinical trials, he said in an email.

"We believe health care professionals should have access to the range of therapy options, opioid and non-opioid, so the best decision can be made for treating the pain of each individual patient," he said.

Doctors writing Thursday in the New England Journal of Medicine said the opioid epidemic is closely tied to a quadrupling of prescriptions over a decade and liberalized use of the drugs due to heightened focus on pain management.

"In this new model, physicians, dentists and nurse practitioners - rather than drug cartels and street dealers - play prominent roles in escalating drug use," wrote Jeanmarie Perrone of the University of Pennsylvania and Lewis Nelson of New York University School of Medicine.

The two called for better prescription drug monitoring programs, which track prescriptions and help doctors identify aberrant behavior such as might occur when a new patient complaining of chronic pain shows up at their office.

In an email, Nelson said he also supported the idea of a label change that would block the prescribing of opioids for chronic, non-cancer pain.

"While physicians are fully allowed to prescribe in this manner, patients, providers and insurance companies may reconsider," he said. "Pain management involves safe use of medication for the preservation of function, not simply pain relief."

Ellen Gabler of the Journal Sentinel staff reported from Bethesda; John Fauber reported from Milwaukee.

About Ellen Gabler

Ellen Gabler is an investigative reporter and assistant editor who has covered health and regulatory issues and specializes in data analysis. Her recent reporting has exposed shortcomings with clinical laboratories, including a lack of transparency in the quality of labs and accrediting organizations that oversee them. Her 2013 examination of flaws in the nation's newborn screening programs led to reform throughout the country.

About John Fauber

John Fauber is an investigative medical reporter who focuses on conflicts of interest in medicine and how drug and medical device companies and the FDA influence the practice of medicine. He has won more than two dozen national journalism awards.